/* * This file is subject to the terms and conditions of the GNU General Public * License. See the file "COPYING" in the main directory of this archive * for more details. * * Copyright (C) 1994 - 1999, 2000 by Ralf Baechle and others. * Copyright (C) 2005, 2006 by Ralf Baechle (ralf@linux-mips.org) * Copyright (C) 1999, 2000 Silicon Graphics, Inc. * Copyright (C) 2004 Thiemo Seufer * Copyright (C) 2013 Imagination Technologies Ltd. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef CONFIG_HOTPLUG_CPU void arch_cpu_idle_dead(void) { play_dead(); } #endif asmlinkage void ret_from_fork(void); asmlinkage void ret_from_kernel_thread(void); void start_thread(struct pt_regs * regs, unsigned long pc, unsigned long sp) { unsigned long status; /* New thread loses kernel privileges. */ status = regs->cp0_status & ~(ST0_CU0|ST0_CU1|ST0_FR|KU_MASK); status |= KU_USER; regs->cp0_status = status; lose_fpu(0); clear_thread_flag(TIF_MSA_CTX_LIVE); clear_used_math(); atomic_set(¤t->thread.bd_emu_frame, BD_EMUFRAME_NONE); init_dsp(); regs->cp0_epc = pc; regs->regs[29] = sp; } void exit_thread(struct task_struct *tsk) { /* * User threads may have allocated a delay slot emulation frame. * If so, clean up that allocation. */ if (!(current->flags & PF_KTHREAD)) dsemul_thread_cleanup(tsk); } int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src) { /* * Save any process state which is live in hardware registers to the * parent context prior to duplication. This prevents the new child * state becoming stale if the parent is preempted before copy_thread() * gets a chance to save the parent's live hardware registers to the * child context. */ preempt_disable(); if (is_msa_enabled()) save_msa(current); else if (is_fpu_owner()) _save_fp(current); save_dsp(current); preempt_enable(); *dst = *src; return 0; } /* * Copy architecture-specific thread state */ int copy_thread(unsigned long clone_flags, unsigned long usp, unsigned long kthread_arg, struct task_struct *p) { struct thread_info *ti = task_thread_info(p); struct pt_regs *childregs, *regs = current_pt_regs(); unsigned long childksp; childksp = (unsigned long)task_stack_page(p) + THREAD_SIZE - 32; /* set up new TSS. */ childregs = (struct pt_regs *) childksp - 1; /* Put the stack after the struct pt_regs. */ childksp = (unsigned long) childregs; p->thread.cp0_status = read_c0_status() & ~(ST0_CU2|ST0_CU1); if (unlikely(p->flags & PF_KTHREAD)) { /* kernel thread */ unsigned long status = p->thread.cp0_status; memset(childregs, 0, sizeof(struct pt_regs)); ti->addr_limit = KERNEL_DS; p->thread.reg16 = usp; /* fn */ p->thread.reg17 = kthread_arg; p->thread.reg29 = childksp; p->thread.reg31 = (unsigned long) ret_from_kernel_thread; #if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX) status = (status & ~(ST0_KUP | ST0_IEP | ST0_IEC)) | ((status & (ST0_KUC | ST0_IEC)) << 2); #else status |= ST0_EXL; #endif childregs->cp0_status = status; return 0; } /* user thread */ *childregs = *regs; childregs->regs[7] = 0; /* Clear error flag */ childregs->regs[2] = 0; /* Child gets zero as return value */ if (usp) childregs->regs[29] = usp; ti->addr_limit = USER_DS; p->thread.reg29 = (unsigned long) childregs; p->thread.reg31 = (unsigned long) ret_from_fork; /* * New tasks lose permission to use the fpu. This accelerates context * switching for most programs since they don't use the fpu. */ childregs->cp0_status &= ~(ST0_CU2|ST0_CU1); clear_tsk_thread_flag(p, TIF_USEDFPU); clear_tsk_thread_flag(p, TIF_USEDMSA); clear_tsk_thread_flag(p, TIF_MSA_CTX_LIVE); #ifdef CONFIG_MIPS_MT_FPAFF clear_tsk_thread_flag(p, TIF_FPUBOUND); #endif /* CONFIG_MIPS_MT_FPAFF */ atomic_set(&p->thread.bd_emu_frame, BD_EMUFRAME_NONE); if (clone_flags & CLONE_SETTLS) ti->tp_value = regs->regs[7]; return 0; } #ifdef CONFIG_CC_STACKPROTECTOR #include unsigned long __stack_chk_guard __read_mostly; EXPORT_SYMBOL(__stack_chk_guard); #endif struct mips_frame_info { void *func; unsigned long func_size; int frame_size; int pc_offset; }; #define J_TARGET(pc,target) \ (((unsigned long)(pc) & 0xf0000000) | ((target) << 2)) static inline int is_ra_save_ins(union mips_instruction *ip, int *poff) { #ifdef CONFIG_CPU_MICROMIPS /* * swsp ra,offset * swm16 reglist,offset(sp) * swm32 reglist,offset(sp) * sw32 ra,offset(sp) * jradiussp - NOT SUPPORTED * * microMIPS is way more fun... */ if (mm_insn_16bit(ip->halfword[1])) { switch (ip->mm16_r5_format.opcode) { case mm_swsp16_op: if (ip->mm16_r5_format.rt != 31) return 0; *poff = ip->mm16_r5_format.imm; *poff = (*poff << 2) / sizeof(ulong); return 1; case mm_pool16c_op: switch (ip->mm16_m_format.func) { case mm_swm16_op: *poff = ip->mm16_m_format.imm; *poff += 1 + ip->mm16_m_format.rlist; *poff = (*poff << 2) / sizeof(ulong); return 1; default: return 0; } default: return 0; } } switch (ip->i_format.opcode) { case mm_sw32_op: if (ip->i_format.rs != 29) return 0; if (ip->i_format.rt != 31) return 0; *poff = ip->i_format.simmediate / sizeof(ulong); return 1; case mm_pool32b_op: switch (ip->mm_m_format.func) { case mm_swm32_func: if (ip->mm_m_format.rd < 0x10) return 0; if (ip->mm_m_format.base != 29) return 0; *poff = ip->mm_m_format.simmediate; *poff += (ip->mm_m_format.rd & 0xf) * sizeof(u32); *poff /= sizeof(ulong); return 1; default: return 0; } default: return 0; } #else /* sw / sd $ra, offset($sp) */ if ((ip->i_format.opcode == sw_op || ip->i_format.opcode == sd_op) && ip->i_format.rs == 29 && ip->i_format.rt == 31) { *poff = ip->i_format.simmediate / sizeof(ulong); return 1; } return 0; #endif } static inline int is_jump_ins(union mips_instruction *ip) { #ifdef CONFIG_CPU_MICROMIPS /* * jr16,jrc,jalr16,jalr16 * jal * jalr/jr,jalr.hb/jr.hb,jalrs,jalrs.hb * jraddiusp - NOT SUPPORTED * * microMIPS is kind of more fun... */ if (mm_insn_16bit(ip->halfword[1])) { if ((ip->mm16_r5_format.opcode == mm_pool16c_op && (ip->mm16_r5_format.rt & mm_jr16_op) == mm_jr16_op)) return 1; return 0; } if (ip->j_format.opcode == mm_j32_op) return 1; if (ip->j_format.opcode == mm_jal32_op) return 1; if (ip->r_format.opcode != mm_pool32a_op || ip->r_format.func != mm_pool32axf_op) return 0; return ((ip->u_format.uimmediate >> 6) & mm_jalr_op) == mm_jalr_op; #else if (ip->j_format.opcode == j_op) return 1; if (ip->j_format.opcode == jal_op) return 1; if (ip->r_format.opcode != spec_op) return 0; return ip->r_format.func == jalr_op || ip->r_format.func == jr_op; #endif } static inline int is_sp_move_ins(union mips_instruction *ip) { #ifdef CONFIG_CPU_MICROMIPS /* * addiusp -imm * addius5 sp,-imm * addiu32 sp,sp,-imm * jradiussp - NOT SUPPORTED * * microMIPS is not more fun... */ if (mm_insn_16bit(ip->halfword[1])) { return (ip->mm16_r3_format.opcode == mm_pool16d_op && ip->mm16_r3_format.simmediate && mm_addiusp_func) || (ip->mm16_r5_format.opcode == mm_pool16d_op && ip->mm16_r5_format.rt == 29); } return ip->mm_i_format.opcode == mm_addiu32_op && ip->mm_i_format.rt == 29 && ip->mm_i_format.rs == 29; #else /* addiu/daddiu sp,sp,-imm */ if (ip->i_format.rs != 29 || ip->i_format.rt != 29) return 0; if (ip->i_format.opcode == addiu_op || ip->i_format.opcode == daddiu_op) return 1; #endif return 0; } static int get_frame_info(struct mips_frame_info *info) { bool is_mmips = IS_ENABLED(CONFIG_CPU_MICROMIPS); union mips_instruction insn, *ip; const unsigned int max_insns = 128; unsigned int last_insn_size = 0; unsigned int i; info->pc_offset = -1; info->frame_size = 0; ip = (void *)msk_isa16_mode((ulong)info->func); if (!ip) goto err; for (i = 0; i < max_insns; i++) { ip = (void *)ip + last_insn_size; if (is_mmips && mm_insn_16bit(ip->halfword[0])) { insn.halfword[0] = 0; insn.halfword[1] = ip->halfword[0]; last_insn_size = 2; } else if (is_mmips) { insn.halfword[0] = ip->halfword[1]; insn.halfword[1] = ip->halfword[0]; last_insn_size = 4; } else { insn.word = ip->word; last_insn_size = 4; } if (is_jump_ins(&insn)) break; if (!info->frame_size) { if (is_sp_move_ins(&insn)) { #ifdef CONFIG_CPU_MICROMIPS if (mm_insn_16bit(ip->halfword[0])) { unsigned short tmp; if (ip->halfword[0] & mm_addiusp_func) { tmp = (((ip->halfword[0] >> 1) & 0x1ff) << 2); info->frame_size = -(signed short)(tmp | ((tmp & 0x100) ? 0xfe00 : 0)); } else { tmp = (ip->halfword[0] >> 1); info->frame_size = -(signed short)(tmp & 0xf); } } else #endif info->frame_size = - ip->i_format.simmediate; } continue; } if (info->pc_offset == -1 && is_ra_save_ins(&insn, &info->pc_offset)) break; } if (info->frame_size && info->pc_offset >= 0) /* nested */ return 0; if (info->pc_offset < 0) /* leaf */ return 1; /* prologue seems boggus... */ err: return -1; } static struct mips_frame_info schedule_mfi __read_mostly; #ifdef CONFIG_KALLSYMS static unsigned long get___schedule_addr(void) { return kallsyms_lookup_name("__schedule"); } #else static unsigned long get___schedule_addr(void) { union mips_instruction *ip = (void *)schedule; int max_insns = 8; int i; for (i = 0; i < max_insns; i++, ip++) { if (ip->j_format.opcode == j_op) return J_TARGET(ip, ip->j_format.target); } return 0; } #endif static int __init frame_info_init(void) { unsigned long size = 0; #ifdef CONFIG_KALLSYMS unsigned long ofs; #endif unsigned long addr; addr = get___schedule_addr(); if (!addr) addr = (unsigned long)schedule; #ifdef CONFIG_KALLSYMS kallsyms_lookup_size_offset(addr, &size, &ofs); #endif schedule_mfi.func = (void *)addr; schedule_mfi.func_size = size; get_frame_info(&schedule_mfi); /* * Without schedule() frame info, result given by * thread_saved_pc() and get_wchan() are not reliable. */ if (schedule_mfi.pc_offset < 0) printk("Can't analyze schedule() prologue at %p\n", schedule); return 0; } arch_initcall(frame_info_init); /* * Return saved PC of a blocked thread. */ unsigned long thread_saved_pc(struct task_struct *tsk) { struct thread_struct *t = &tsk->thread; /* New born processes are a special case */ if (t->reg31 == (unsigned long) ret_from_fork) return t->reg31; if (schedule_mfi.pc_offset < 0) return 0; return ((unsigned long *)t->reg29)[schedule_mfi.pc_offset]; } #ifdef CONFIG_KALLSYMS /* generic stack unwinding function */ unsigned long notrace unwind_stack_by_address(unsigned long stack_page, unsigned long *sp, unsigned long pc, unsigned long *ra) { unsigned long low, high, irq_stack_high; struct mips_frame_info info; unsigned long size, ofs; struct pt_regs *regs; int leaf; if (!stack_page) return 0; /* * IRQ stacks start at IRQ_STACK_START * task stacks at THREAD_SIZE - 32 */ low = stack_page; if (!preemptible() && on_irq_stack(raw_smp_processor_id(), *sp)) { high = stack_page + IRQ_STACK_START; irq_stack_high = high; } else { high = stack_page + THREAD_SIZE - 32; irq_stack_high = 0; } /* * If we reached the top of the interrupt stack, start unwinding * the interrupted task stack. */ if (unlikely(*sp == irq_stack_high)) { unsigned long task_sp = *(unsigned long *)*sp; /* * Check that the pointer saved in the IRQ stack head points to * something within the stack of the current task */ if (!object_is_on_stack((void *)task_sp)) return 0; /* * Follow pointer to tasks kernel stack frame where interrupted * state was saved. */ regs = (struct pt_regs *)task_sp; pc = regs->cp0_epc; if (!user_mode(regs) && __kernel_text_address(pc)) { *sp = regs->regs[29]; *ra = regs->regs[31]; return pc; } return 0; } if (!kallsyms_lookup_size_offset(pc, &size, &ofs)) return 0; /* * Return ra if an exception occurred at the first instruction */ if (unlikely(ofs == 0)) { pc = *ra; *ra = 0; return pc; } info.func = (void *)(pc - ofs); info.func_size = ofs; /* analyze from start to ofs */ leaf = get_frame_info(&info); if (leaf < 0) return 0; if (*sp < low || *sp + info.frame_size > high) return 0; if (leaf) /* * For some extreme cases, get_frame_info() can * consider wrongly a nested function as a leaf * one. In that cases avoid to return always the * same value. */ pc = pc != *ra ? *ra : 0; else pc = ((unsigned long *)(*sp))[info.pc_offset]; *sp += info.frame_size; *ra = 0; return __kernel_text_address(pc) ? pc : 0; } EXPORT_SYMBOL(unwind_stack_by_address); /* used by show_backtrace() */ unsigned long unwind_stack(struct task_struct *task, unsigned long *sp, unsigned long pc, unsigned long *ra) { unsigned long stack_page = 0; int cpu; for_each_possible_cpu(cpu) { if (on_irq_stack(cpu, *sp)) { stack_page = (unsigned long)irq_stack[cpu]; break; } } if (!stack_page) stack_page = (unsigned long)task_stack_page(task); return unwind_stack_by_address(stack_page, sp, pc, ra); } #endif /* * get_wchan - a maintenance nightmare^W^Wpain in the ass ... */ unsigned long get_wchan(struct task_struct *task) { unsigned long pc = 0; #ifdef CONFIG_KALLSYMS unsigned long sp; unsigned long ra = 0; #endif if (!task || task == current || task->state == TASK_RUNNING) goto out; if (!task_stack_page(task)) goto out; pc = thread_saved_pc(task); #ifdef CONFIG_KALLSYMS sp = task->thread.reg29 + schedule_mfi.frame_size; while (in_sched_functions(pc)) pc = unwind_stack(task, &sp, pc, &ra); #endif out: return pc; } /* * Don't forget that the stack pointer must be aligned on a 8 bytes * boundary for 32-bits ABI and 16 bytes for 64-bits ABI. */ unsigned long arch_align_stack(unsigned long sp) { if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space) sp -= get_random_int() & ~PAGE_MASK; return sp & ALMASK; } static DEFINE_PER_CPU(struct call_single_data, backtrace_csd); static struct cpumask backtrace_csd_busy; static void arch_dump_stack(void *info) { struct pt_regs *regs; static arch_spinlock_t lock = __ARCH_SPIN_LOCK_UNLOCKED; arch_spin_lock(&lock); regs = get_irq_regs(); if (regs) show_regs(regs); else dump_stack(); arch_spin_unlock(&lock); cpumask_clear_cpu(smp_processor_id(), &backtrace_csd_busy); } void arch_trigger_all_cpu_backtrace(bool include_self) { struct call_single_data *csd; int cpu; for_each_cpu(cpu, cpu_online_mask) { /* * If we previously sent an IPI to the target CPU & it hasn't * cleared its bit in the busy cpumask then it didn't handle * our previous IPI & it's not safe for us to reuse the * call_single_data_t. */ if (cpumask_test_and_set_cpu(cpu, &backtrace_csd_busy)) { pr_warn("Unable to send backtrace IPI to CPU%u - perhaps it hung?\n", cpu); continue; } csd = &per_cpu(backtrace_csd, cpu); csd->func = arch_dump_stack; smp_call_function_single_async(cpu, csd); } } int mips_get_process_fp_mode(struct task_struct *task) { int value = 0; if (!test_tsk_thread_flag(task, TIF_32BIT_FPREGS)) value |= PR_FP_MODE_FR; if (test_tsk_thread_flag(task, TIF_HYBRID_FPREGS)) value |= PR_FP_MODE_FRE; return value; } int mips_set_process_fp_mode(struct task_struct *task, unsigned int value) { const unsigned int known_bits = PR_FP_MODE_FR | PR_FP_MODE_FRE; unsigned long switch_count; struct task_struct *t; /* If nothing to change, return right away, successfully. */ if (value == mips_get_process_fp_mode(task)) return 0; /* Only accept a mode change if 64-bit FP enabled for o32. */ if (!IS_ENABLED(CONFIG_MIPS_O32_FP64_SUPPORT)) return -EOPNOTSUPP; /* And only for o32 tasks. */ if (IS_ENABLED(CONFIG_64BIT) && !test_thread_flag(TIF_32BIT_REGS)) return -EOPNOTSUPP; /* Check the value is valid */ if (value & ~known_bits) return -EOPNOTSUPP; /* Setting FRE without FR is not supported. */ if ((value & (PR_FP_MODE_FR | PR_FP_MODE_FRE)) == PR_FP_MODE_FRE) return -EOPNOTSUPP; /* Avoid inadvertently triggering emulation */ if ((value & PR_FP_MODE_FR) && raw_cpu_has_fpu && !(raw_current_cpu_data.fpu_id & MIPS_FPIR_F64)) return -EOPNOTSUPP; if ((value & PR_FP_MODE_FRE) && raw_cpu_has_fpu && !cpu_has_fre) return -EOPNOTSUPP; /* FR = 0 not supported in MIPS R6 */ if (!(value & PR_FP_MODE_FR) && raw_cpu_has_fpu && cpu_has_mips_r6) return -EOPNOTSUPP; /* Proceed with the mode switch */ preempt_disable(); /* Save FP & vector context, then disable FPU & MSA */ if (task->signal == current->signal) lose_fpu(1); /* Prevent any threads from obtaining live FP context */ atomic_set(&task->mm->context.fp_mode_switching, 1); smp_mb__after_atomic(); /* * If there are multiple online CPUs then wait until all threads whose * FP mode is about to change have been context switched. This approach * allows us to only worry about whether an FP mode switch is in * progress when FP is first used in a tasks time slice. Pretty much all * of the mode switch overhead can thus be confined to cases where mode * switches are actually occurring. That is, to here. However for the * thread performing the mode switch it may take a while... */ if (num_online_cpus() > 1) { spin_lock_irq(&task->sighand->siglock); for_each_thread(task, t) { if (t == current) continue; switch_count = t->nvcsw + t->nivcsw; do { spin_unlock_irq(&task->sighand->siglock); cond_resched(); spin_lock_irq(&task->sighand->siglock); } while ((t->nvcsw + t->nivcsw) == switch_count); } spin_unlock_irq(&task->sighand->siglock); } /* * There are now no threads of the process with live FP context, so it * is safe to proceed with the FP mode switch. */ for_each_thread(task, t) { /* Update desired FP register width */ if (value & PR_FP_MODE_FR) { clear_tsk_thread_flag(t, TIF_32BIT_FPREGS); } else { set_tsk_thread_flag(t, TIF_32BIT_FPREGS); clear_tsk_thread_flag(t, TIF_MSA_CTX_LIVE); } /* Update desired FP single layout */ if (value & PR_FP_MODE_FRE) set_tsk_thread_flag(t, TIF_HYBRID_FPREGS); else clear_tsk_thread_flag(t, TIF_HYBRID_FPREGS); } /* Allow threads to use FP again */ atomic_set(&task->mm->context.fp_mode_switching, 0); preempt_enable(); return 0; }